Red Blood Cells & Rocket Launches – PediaCast 396

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This week we answer your questions about laryngomalacia, noise sensitivity and G6PD deficiency. We also consider the recent test flight of Falcon Heavy and how watching a rocket launch can ignite a child's love of science. We hope you can join us!

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Announcer 1:This is PediaCast.

[Music]

Announcer 2:Welcome to PediaCast, a pediatric podcast for parents. And now, direct from the campus of Nationwide Children's, here is your host, Dr. Mike.

Dr. Mike Patrick: Hello everyone, and welcome once again to PediaCast. It's a pediatric podcast for moms and dads. This is Dr. Mike, coming to you from the campus of Nationwide Children's Hospital. We're in Columbus, Ohio.

It's Episode 396 for February 8th 2018. We're calling this one, "Red Blood Cells and Rocket Launches". I want to welcome everyone to the program. We have another information packed show for you this week as we consider answers to your questions, that's right.

This is an episode of the program you created. I put out a call for questions a couple weeks back and many of you responded. We'll answer three of those questions today and I'd love to hear more from you; what's on your mind, what questions do you have, what topics would you like us to cover on the program. And, I'll let you know how you can get in touch in just a couple minutes along with the rundown of the three questions that we'll be answering today.

But first, did you watch the test launch of "Falcon Heavy" from SpaceX this past Tuesday? A couple days ago, it was February 6th 2018, if you're listening to this episode at a future date. It was amazing to say the least. Now granted, this is coming from a space geek, you know, I'm still sad about the end of the space shuttle era.

00:01:50

You know, the idea of sitting down with a pile of Legos and building a rocket or a spaceship, you know, still holds some interest for me, you know. Our family attended space shuttle launches whenever we could. When we lived in Florida—visited the Kennedy Space Center. I loved eating lunch under the suspended Saturn V Rocket. When you take the bus tour at Cape Canaveral.

Many of you know what I'm talking about. And, even if you don't get excited about the launch of a rocket with 28 engines that were strapped together in 3 cords and generating 5 million pounds of thrust, which by the way, is twice as much thrust as any rocket in production today. Even if that doesn't get you excited, perhaps there is someone in your house who would be excited like your kids.

And, what a wonderful thing to watch together especially if your kid likes space, you know, if they're Star Wars fans, this is like—this is as close to Star Wars as real life actually gets. And you know, if they have an interest in science or you know, maybe they don't know that they like space and science. And, they won't know until you start talking and exploring together. And, this will be a great starting place.

00:03:00

I think they would really enjoy watching that launch. And, it's not just the launch, SpaceX put out a webcast with live coverage of the entire event which you can watch in its entirety. And, I'll put a link in the show notes so you can find it easily and replay it on Youtube over at pediacast.org. Just click on the show notes for this Episode 396 and I'll put a link to it there for you.

But the webcast is really amazing. It's about a half-hour long and SpaceX team—what an exciting group they are. I mean, they genuinely look thrilled with this endeavor. And, they take you through, sort of the building and history of the Falcon Heavy; how it works, where it's going, why it's important.

But they were realistic too. I mean, as you listen to them explain all of this before the actual launch, they're like, "Well, we hope this happens and this is what we intend" and then, Elon Musk, the head of SpaceX, he put the chance of success of getting this thing off the ground at somewhere between 50 and 75 percent, which may have helped the ratings a little bit because in your mind, you think, "Hmm, 50 to 75 percent chance of a successful launch. Does that mean they're gonna scrub it or does that mean that things could blow up on the launch pad?"

And you know, so he sets up something like that. I think, you know, you may get more eyes on the event. But the bottom line is it was truly amazing. I mean, they're on a historical launch pad 39A. Same place as Neil Armstrong, and Michael Collins, and Buzz Aldrin took off for the moon. So lot's of history there.

And then, to see this thing not only go up but for the two outer cords, so these are basically two separate rockets. To see them come back down and land in tandem back at the space center—I mean, seriously, your kids are gonna love watching this. Trust me.

And then, the icing on the cake was of course the rocket's payload—it was a test. They didn't wanna put anything, you know, that someone else had paid for in this. So, they put a Tesla—electric car. In fact, it was Elon Musk's personal Tesla roadster from like 2008.

00:05:05

It's a red convertible and you've got a space-suited astronaut dummy known as "Starman" at the wheel. So really, there's a sports car now with the top down and an astronaut dummy at the wheel, you know, out there in space right now—that's pretty crazy.

Now, they did have a little misstep. They wanted it to orbit the Sun and not orbit the Earth but actually orbit the Sun and orbit the intersects, both earth and Mars, which would have been really cool. And, they said it would have stayed in this orbit for, you know, a billion years.

But as it turns out, they overshot where they had to inject to get out of the Earth's orbit and put it into an orbit around the Sun and they didn't do that quite right. And so, now it's just heading out towards the asteroid belt, which really kinda stinks.

But, you can see images of Starman cruising through the Solar System with the Earth in the background, driving this car. I mean, it's really cool. I know I'm all geeky excited over this but y'all understand what I mean once you see the video. And, again, you can find it easily in the show notes for this Episode 396.

Alright, so what are we talking about today? We're gonna answer your questions. First up is laryngomalacia and I know it's a mouthful. It's a huge word, little difficult to pronounce. We'll break it down—explain exactly what it means. You know, the bottom line is it's a common cause of noise breathing in babies. And, we'll explain what it is, the problems, the causes, what you can do about it.

Another listener has a son who does not like loud noises so we'll consider that particular issue. And then it's on to a G6PD deficiency, which affects red blood cells. It's a genetic disease. You may not be familiar with it but it affects 400 million people worldwide and it's a really interesting disease.

00:06:56

So if you're like me and you enjoy learning about Medical Science, in addition to Space Science, stick around and I'll do my best to explain the complexities of G6PD deficiency in terms you can understand, hopefully, that's the plan. But also, in a way that doesn't short-change the science behind this very interesting genetic disorder. So that's coming your way in a couple of minutes as we consider red blood cells.

Very quickly, I mentioned sending your questions or comments for a future episode of the program. Easy thing to do, just head over to pediacast.org, click on the contact link and send me your question or your comment, or if you wanna point me in the direction of a new story, a journal article—whatever's on your mind. Let me know and we'll try to get that on the program for you.

Also, wanna remind you the information presented in every episode of PediaCast is for general educational purposes only. We do not diagnose medical conditions or formulate treatment plans for specific individuals. So if you have a concern about your child's health, be sure to call your doctor and arrange a face-to-face interview and hands-on physical examination.

Also, your use of this audio program is subject to the PediaCast's terms of use agreement which you can find at pediacast.org.

Let's take a quick break and then I will be back to talk more about laryngomalacia, noise sensitivity and G6PD deficiency. It's all coming up right after this!

[Music]

00:08:48

We have a question from Jennifer in Texas. Jennifer says, "Hi Dr. Mike, my daughter was recently diagnosed with laryngomalacia at 17 months of age after we took her to an Ear, Nose and Throat doctor to the sounds she made while sleeping. My understanding is that most kids outgrow this condition at around 18 months. So, we found out late and near the end. When my husband and I read about the symptoms, we recognized things from when she was younger and we were able to connect the dots. Can you go over laryngomalacia and the symptoms parents might see."

Well absolutely, Jennifer. And, thanks by the way for the question—really do appreciate that. I'm sure there are plenty of other parents out there who have heard of laryngomalacia because it's not exactly uncommon.

Maybe you have a child who's diagnosed with it to have but you still have some lingering questions. So let's try to answer those and I think a good place to start is just to break that word down: laryngomalacia.

Two parts to it, laryngo—and laryngo, just refers to the larynx. And, the larynx is the upper part of the airway so from the back of the throat down to the level of the vocal cords—that would be considered the larynx. So we're really just talking about the upper airway.

And then, malacia is—when it's used in medicine, it means an abnormal softening of tissue. So, this word would mean an abnormal softening of the larynx, which is kinda interesting because we don't really think that it's caused by abnormal softening of the larynx. But there was a time when we did and so that's the name that has sorta stuck.

Now, one other thing that we would wanna bring into the definition is that it's—we also use the word "supraglottic". And supraglottic, "supra" means above and "glottic" refers to the vocal cords.

00:10:38

So, if as a parent, you're coming across, you know, looking up laryngomalacia, it's a big word to begin with. And then, the definition of laryngomalacia—it says collapse of the supraglottic structures during inspiration. So, you know, when you come across that like "What in the world? Now we got another big word."

But really, we're just sorta talking about the same thing here. Larynx means above the vocal cords. Supraglottic also means above the vocal cords. And so, this would seem that this structure above the vocal cords is sort of abnormally soft. And so, when you breathe in, it collapses on itself.

And again, we'll talk about this what's really soft and what exactly is going on. We'll get to in a minute.

One additional definition, something else you may have heard of is the epiglottis. And, the epiglottis is a flap of tissue that covers the airway when you swallow. So again, glottis kinda refers to the vocal cords. "Epi" means, well, above the vocal cords. In fact, it's even above the larynx.

So the larynx runs from the epiglottis, so back of the throat where the epiglottis covers the larynx when you swallow so food doesn't go down into the airway. And then the larynx runs down to the level of the vocal cords.

So the airway above the vocal cords collapses inward on itself when you breathe in. And think about it like this, a straw collapsing inward when you try to suck up a really thick milkshake. I mean that's what's happening. So think about that and the straw collapses in on itself. And then of course, that can make some noise because you are creating a smaller area that the air has to rush through and so that's gonna make a noise every time that the baby breathes in and that area of the airway sort of collapses in on itself.

So why does this happen? Well again, we used to think that it happened because the tissue is just softer, maybe the cartilage hadn't really matured yet, and so, because it was softer, it was easier for it to collapse in on itself when babies breathed in.

00:12:47

It's still not exactly clearly defined why this happens and different mechanisms may end up applying to different babies. So what causes in one baby may be a little bit different than in another baby. But sort of—some of the proposed mechanisms, again, this maturation—could the airway be more floppy? Can it just be softer?

That really was the number one hypothesis and why it has the name laryngoamalacia. However, more recently, histologic study—so, when they take samples of the tissue and look at the cells, there's no difference in how those cells are made up in babies with laryngomalacia and babies without it. The tissue looks exactly the same.

So this hypothesis is unlikely but it sure is an easy one to explain so, you know, even though it's not evidence-based, I'm sure there's still a lot of physicians out there who say, "Hey, the airway's more floppy and that's why it happens" cos it's sort of easy just to say that.

But it's probably not actually softness of that tissue. Another possibility is redundant soft tissue in the larynx. And so, what that means is there's just more soft tissue there than there needs to be. And, that can sort of make it so that the structure is sort of floppy because, you know, the tissue is not tight or tense as it runs through the larynx.

So, you know, from a histological standpoint from looking at the tissue and the cells—everything looks the same, there's just more of it and it's not exactly tight. And then, there's other anatomic variations, you know, just the plumbing, may be a little different from one kid to another from the epiglottis—that flap that protects the airway when you swallow so food doesn't get down to the glottis or the vocal cords.

So there may be some variations there but usually in laryngomalacia, if you look at that area with a scope, the anatomy looks normal.

00:14:46

And then, another possibility is that there's some swelling to the tissue in that area—maybe related to gastroesophageal reflex so stomach acid comes up the esophagus and then babies—it goes down, it gets past the epiglottis, down into the airway and can cause some soft tissue swelling.

So there has been some, you know, question of whether this is caused from reflux—stomach acid reflux, however again, for most babies with laryngomalacia, if you look down there with a scope, you don't necessarily see swelling, and of course, reflux is common in lots and lots of babies.

And so, a lot of babies that have laryngomalacia also have reflux but it doesn't mean that one thing causes the other. It just can mean two things are happening in the same baby but that reflux happens in lots of babies. So why doesn't laryngomalacia and noisy breathing happen in all of them?

And then, the final mechanism which I think is becoming the most favored theory is that there's probably a neuromuscular mechanism. So you know, the larynx—it's tissue and there's some smooth muscle that's involved and sorta keeping it rigid and maybe there's some laxity in the musculature that's really more related to, you know, the baby's neuromuscular system not being quite developed well enough.

And this is supported by the fact that laryngomalacia does typically fluctuate with state of consciousness. So when babies sleep or they're really tired and they're just—they're more floppy and relaxed, you hear the laryngomalacia—the noise, the strider that's made because of this floppy airway. You're more likely to hear it.

So if that looseness, you know, fluctuates with whether your baby is sleeping or not, then maybe it has more to do with muscular tone and the nervous system telling those muscles, you know, whether you're gonna be sort of tight or whether you're gonna be loose.

00:16:46

And when you're loose, it's more likely that the airway will collapse in on itself. So I think the more favored theory these days, and again, it may differ from one baby to another, exactly what's going on but that it is more of a neuromuscular mechanism. It has more to do with the nerves and the muscles not being quite mature yet.

So what symptoms do we see? Well again, as the airway collapses in on itself with breathing in, you're gonna have an extra noise with every breath in and it's a noise we call strider. And it's not something you wanna diagnose on your own at home. You don't wanna, you know, listen to your noisy baby breathing and say, "Oh, that's strider."

If your baby's making a funny noise every time they breathe in, you wanna see a medical provider so someone can listen and make sure that it's really what it is—that it's not wheezing, that it's not something else that's going on.

And with laryngomalacia, usually the strider is loudest when they're about 4-8 months of age. And then, by 12-18 months of age, the strider has resolved completely. And just has Jennifer had mentioned, "We're kind of at the end of this right now", and hopefully that's the case for you Jennifer. But it does usually resolve by about 12-18 months of age.

Sometimes it can last a little longer. And then, it does become more intense during upper respiratory tract infections, which sort of, makes sense because babies, you know, if you're breathing through a lot of mucus in the nose or there's mucus down in the lungs, you have to take breaths that have more pressure. So you have to, sort of, breathe in with more pressure in order to get the air through the mucus.

And so, because you're increasing the pressure of that breath in, it's more likely that the airway's gonna collapse. Just like if you suck harder with a straw and a thick milkshake, the harder you suck, the more likely it is that the straw is gonna collapse in on itself.

And then, when the baby's relaxed, when they're sleeping, when they're feeding. And then, in fact, in very mild cases, it might only be present during sleep.

00:18:46

We also see babies have other, sorta, airway issues along with laryngomalacia—very common. So, they could have snoring, they can have something called tracheomalacia, which is sort of a similar thing but it's happening below the level of the vocal chords. So again, there's sort of an inward collapse on itself which can also cause strider.

So tracheomalacia may be going on. Swallowing dysfunction or/and feeding difficulties and then we—a lot of these kids do have acid reflux. But again, so do very many babies who don't have laryngomalacia. So sometimes, it is hard to know whether the reflux is causing this or it's just there.

And so, some of these babies will get treated for their reflux and if that helps, great, but a lot of time it doesn't because the reflux is not really what's causing the laryngomalacia to begin with.

But there's still some controversy about that and certainly, you know, if your doctor is saying, "Hey, let's try a anti-acid tight medicine to see if it helps" you know, then certainly worth trying. But don't be surprised if it doesn't help.

This can occur just an isolation and in fact, usually that's the case. But, there are some congenital syndromes where you have more likely to have laryngomalacia. So, Trisomy 21 or Down syndrome is one of those, 22 q's and other—also known as Digeorge Syndrome, both things that we've talked about here on this podcast before.

But just because you see laryngomalacia, doesn't mean those other things are going on but it is a common occurrence in those particular conditions. And then the severity really can range, you know, from it being just a simple noisy breathing. You just, you know, there—they don't seem like they're having any trouble breathing. They're feeding fine. They're sleeping well. They're just loud every time they breathe.

And so that would be sort of the mild form. And then, there's the more severe form where babies really look like they're working harder to breathe. You can see some retractions or some sucking in at the skin above the breastbone and below the ribs.

00:20:44

And then, some babies, you know, they have so much trouble breathing especially when they're eating—that they can feed poorly, they can start to not gain weight or even lose weight, or have what we call ferio to thrive.

So there is this range of severity, most cases are mild. But there are some severe cases where it really does impact the child's health. It's not just simple noisy breathing, it really is causing them to not grow well and to have other problems.

Also, laryngomalacia, this is important, does not usually cause a hoarse voice. So, a hoarse voice is usually more of an issue with the vocal chords themselves, so you wanna think about something else that's going on.

And there are lots of other things that can cause strider. So again, just because your baby's making noise and pediatric provider has told you, "Hey, that's strider" does not mean that it's laryngomalacia. A croup can cause strider. A foreign body in the airway can do it. Epiglottitis which is the epiglottis that, again, that flap that protects the airway when you swallow food—that can become swollen and actually obstruct the airway.

And, you know, fortunately, we don't see that as much as we did when years passed because of the Haemophilus Influenza Vaccine. It was usually Hib that would cause epiglottitis and that killed a lot of kids.

But since that immunization and not nearly as much Haemophilus type B out there in the community, we don't see that nearly as often. And so, that's a good thing. But it is one of the potential causes of strider.

Now, those are a little bit different because they typically croup a foreign body. Epiglottitis usually would be, sort of, an acute onset. It suddenly starts, whereas laryngomalacia, it would be something that was more happening day-to-day even sometimes from birth.

And you know, by the time they're 4-6 months old, things are getting a little worse and then finally, 12-18 months, things are getting better. So it's more of a chronic presentation compared to those other things.

But there are other things that can cause chronic strider as well. You know, if you had a premature baby who had a breathing tube down, they could have some scar tissue around the level of the vocal chords that could cause similar thing. Vocal chord paralysis, they could have what's called a vascular ring or blood vessels aren't formed exactly right and they travel around the airway, and can cause some impedance.

00:23:01

And so, air is not flowing well and can make some noise. They can be cysts, there can be what are called a hemangiomas which are little tumors made of blood vessels. So, lots of different things can do this. And again, this is not something that you hear your baby breathing noisily and you say, "Oh, it must just be laryngomalacia"

You definitely wanna see your doctor and have them be the one to make that diagnosis. So how do you make the diagnosis of laryngomalacia? In a lot of times, just the history and physical. A good clinician can make that diagnosis based on how it's presenting, how they sound, how the baby's (23:35 unintelligible). You know, the whole history and physical combined together can give you that sense that this is what's going on.

It can be confirmed with a scope, so you can go see an Ear, Nose, and Throat doctor. They can use a flexible—what we call laryngoscopy, so they put a optical scope down and actually look to see what's going on and they can see that inward collapse and everything else looks normal, so there's no other explanation.

And then, that would confirm the diagnosis of laryngomalacia. But that doesn't mean that every child with suspected laryngomalacia needs a scope. So, experienced providers can diagnose mild cases of this clinically. But you know, it's never wrong if you want a confirmation and certainly, you'd wanna do the scope if there are severe symptoms and you wanna make sure there's not something else or different that's going on.

But in kids with mild cases who really are just, sort of, noisy breathers and they look great, they're growing well, they're feeding well, they're sleeping well—no other issues. You know, scopes also have risks associated with them. And so, you'd want a provider who'd kinda walks down what are the risks and the benefits of doing a scope or not doing a scope. And then, kinda making that decision jointly together.

But certainly, if there's significant symptoms, you know, progressive strider, that noise is just getting worse, you know, your baby has episodes where they stop breathing or they look blue, they really are failing to thrive, you know, any of those things. You definitely would want more emergent attention and scope would certainly, you know, be one way to go to look at what's going on down there.

00:25:07

In terms of treatment, that really depends on severity. The vast majority of kids have a mild form. It's simply noisy breathing. It resolves on its own by 12-18 months of age. Really, just parents need reassurance. The babies needs a little tincture of time and that things are gonna get better.

Again, if they have gastroesophageal reflux, you know, some would try treating that to see if it makes a difference but stopping that treatment if you're not seeing any improvement. I mean, you have to give a little bit of time but, you know, if few weeks of that or a month, you know, it's not helping, it's probably not going to help.

But again, that's something you talk about—risk benefit, with your child's doctor and walk that path to see if that's something that you would wanna try. But most of the time, it does not work.

You know, if a baby is failing to thrive, maybe they're having a bit more difficulty breathing while they're waiting for this to sorta correct on its own then high calorie diet can help them through that. So they're not eating as much, you wanna pack more calories in with each feeding.

And then, really severe cases, you do try to treat any underlying airway abnormality that might be present. So remember, I said if there's too much tissue, it's sorta redundant tissue; there have been some surgeries that can remove some of that redundant tissue and very severe cases.

But you have to be careful because if you cause scarring in the course of doing that, you know, then you're gonna have other airway difficulties because scar tissue can also impede the flow of air. And so again, really looking at risks versus benefits and how severe is this, and coming up with some things that you're gonna do.

But there are surgeries that can correct it in the most severe of cases. But again, those do come with their own risks. And, always considering risks versus benefits is a good idea as parents and families. And, doctors and surgeons all decide together what's right for a particular child given their unique set of circumstances.

00:27:02

So that is laryngomalacia in a nutshell, Jennifer. It usually gets better on its own. It's usually mild, usually can be diagnosed without, you know, without a scope. But when there are questions, certainly see an Ear, Nose and Throat doctor. And when it's severe, seeing someone—always a good idea.

And always a good idea, you know, if it's gonna give you peace of mind. If your baby is a noisy breather and your doctor is saying, "Oh, it's laryngomalacia." You know, if you need that peace of mind, seeing an Ear, Nose and Throat doctor is never gonna be a bad idea just to get that confirmation and if it's gonna help you sleep better at night because that's important for parents, too.

So hope that helps and, Jennifer, as always, thanks so much for the question.

[Music]

00:28:12

Next up is Suzanne from New Hampshire. Her question is—there aren't as many complicated words and complex things to visualize with this one. So, I'll give you a little bit of a break. But then, when we get to G6PD deficiency, there's a little more science involved there.

So Suzanne in New Hampshire says, "I would first like to say how much I enjoy listening to your podcast. I have three children: one, four and seven years of age. And your program has been very informative through the years. I'm not sure you've covered this on the show but I have a question about noise sensitivity with my seven-year-old son.

He's always been sensitive to loud noises but I thought at seven, he should have outgrown it by now. One day, we were at a basketball game and after hearing the buzzer, he wanted to leave because he said it was too lout and he did not want to hear it again.

Also, when I run my blender for morning smoothies, he covers his ears. When I ask him why, he says, "I just have sensitive ears."

00:29:02

Is this something he will outgrow or something I should be worried about? What's normal? What's not? Thank you again. -Suzanne."

So great question, Suzanne. And, this is a common occurrence—kids not liking really loud noises. And in fact, there are a lot of adults who also do not like really loud noises. So let's begin with a couple of distinctions.

First, we're not talking about dangerously loud noises, right? This is an important distinction because dangerously loud noises tend to be uncomfortable. So it would be understandable that your child would not like those. And by the way, dangerously loud noises don't have to be uncomfortable. You know, listening to loud music over a prolonged period, repeatedly, that can damage your hearing.

But what you described here in brief bursts, so not prolonged exposure, probably are not dangerous as long as your child's not standing right next to the basketball buzzer every time it goes off. Or, has his head next to the blender and you leave it on for a very long time. That I'm sure, you know, I don't think any of us would like that.

So what we're talking about here though is bursts of loud noises but they're normal loud noises that he doesn't like. So let's come back to that in a second.

The other distinction I think is important is he's not bothered by everyday regular volume noises. You know, sensitivity to everyday noises—so just the noises that we generally encounter, that we would consider just normal noises for most people. Some people are sensitive to those normal noises and that's a condition that we would call hyperacusis.

It's somewhat rare. This occurs, again, when everyday noises are experienced as loud and/or bothersome when others are hearing that same noises are not bothered by it. You know, everyone else just experiences those noises as normal. And there are some medical conditions associated with hyperacusis. So that sensitivity to just everyday noises including some neurology type diseases that involve nerve. So Bell's palsy would be an example, Meniere's Disease, which is usually accompanied by dizziness or vertigo.

00:31:02

Sometimes you also get ringing or buzzing in the ears or tinnitus. But those, again, are more—the signals that are coming from the nerve to the brain are sorta abnormal and so that's the reason that you're perceiving those in sort of a different way.

It can also be associated with Post-traumatic Stress Disorder and with autism spectrum disorders which isn't surprising because sensory processing differences are common in autism, so, not necessarily that there's an abnormality of the nerves sending the signals. But instead, there is abnormality in the way that those normal signals are perceived.

And so, in autism, you know, we do have sensory processing differences and hearing is a sense. So noise sensitivity in kids to everyday noises—it's not diagnostic of autism. But if your child is sensitive to everyday noises on a regular recurring basis, you know, be sure to talk to your child's doctor. Doesn't mean he or she has autism but developmental screening and asking lots of other questions can help to clarify what's going on.

But again, this doesn't really describe Suzanne's son, right? He's not sensitive to everyday noises and we're not talking about prolonged dangerous noises. It's simply loud but brief and maybe a little unpredictable ann unexpected noises which for some kids is an issue because there is that startle factor involved.

I mean, if you're sitting in a basketball game, watching the players running up and down the court, you aren't necessarily paying attention to the time and all of a sudden there's a blast of noise, you know, you jump, your hands go to your ears, you heart's racing. No wonder you just wanna leave especially if you have an underlying dislike to brief, loud, unexpected noises.

So, Suzanne, I would say in many cases, dislike of these loud noises is normal. It usually corrects itself with time. And you wanna kinda warn your child, as much as possible, when to expect those loud noises, you know, at the same time.

00:33:00

I mean, what I'm saying is, if you're in a basketball game together, you know, maybe have him cover his ears when the time is running out and you know that it's gonna happen. You know, so that he can expect it and it's not a sudden startle. And just go ahead and cover your ears, you know, and then it's gonna happen and it'll be good cos you enjoy the basketball game.

And so, we wanna also reinforce, you know, interest in sports. And, get out and about and not staying at home. You know, so that warning and preparation may be helpful but at the same time, you also don't wanna put too much focus on the issue, you know. You don't necessarily wanna make it a bigger deal than it is especially if you wanna kind of extinguish that behavior over time.

And of course, always a good idea to talk to your child's doctor about this especially if the sound sensitivity is spreading to everyday noises or the aversion is affecting daily living in one way or another. Certainly makes sense, you know, to verify your child's ear exam is normal, that the hearing test shows no concerns, that development is on track, there are no other issues.

And then once you've done that, you know, then you know, well, he just doesn't like brief loud noises which is not, you know, really a concern for children of this age. And you know, something that they'll probably outgrow. So hope that helps, Suzanne, thanks for sending your question.

The bottom line, talk to your child's doctor about it next time you're in and sooner if things get worse or additional concerns crop up.

Our next question comes from Dr. Zucker in Israel. Dr. Zucker says, "Hi Dr. Mike, a lot of my patients have G6PD deficiency. I know they are not allowed certain medications and creams and I know they cannot eat fava beans. I was wondering if you have done a show on G6PD deficiency and wondered hoe prevalent it is. I see 3 people a day with this condition here in Israel. Thanks"

So a great topic idea from Dr. Zucker and G6PD is a really interesting disease. And, it's one you may not have heard of before but it does affect the lives of many families. So let's start with the definition which will help us understand the cause of this disorder.

00:35:04

So G6PD stands for Glucose-6-Phosphate Dehydrogenase. Now, I promise that's the last time I'll say those words—that's why we call it G6PD because we don't wanna say those words every time. And G6PD is a chemical so it's a chemical in the body. We're gonna be paying attention to this chemical in the context of red blood cells.

So the red blood cells circulate in your blood, deliver oxygen to tissues, take away carbon dioxide to the lungs so it's involved in gas exchange. And G6PD is a chemical in those red blood cells, specifically, it's an enzyme.

Now you remember from high school biology that enzymes are molecules, they're usually proteins and they help chemical reactions take place. So in their presence, one molecule reacts and turns into or facilitates a reaction so that another molecule is made by way of chemical reaction.

And with the enzyme in place, you know, it may help line up the molecules that need to be there to form the reaction. They just—in their presence, the reaction takes place more quickly and in greater amounts then would occur without the presence of the enzyme.

So we say the enzyme is acting as a catalyst because it's helping a chemical reaction take place. Now in the case of G6PD, the enzyme is facilitating the conversion of one molecule to a different molecule. And in the process of that conversion, a third molecule gets converted to a fourth molecule.

So this is very complicated. But the bottom line is, to get to that fourth molecule, you need G6PD there in order to facilitate the first step of the overall reaction. And it's that fourth molecule that's particularly important; it's called NADPH.

00:37:03

So it's important that you have G6PD to help make large amounts of the NADPH. Now again, the location of this chemical reaction is in red blood cells. Again, you'll remember from high school biology that these cells contain hemoglobin and the hemoglobin carries oxygen to all parts of your body—so very important job.

So as oxygen interacts with hemoglobin, so hemoglobin's carrying the oxygen. But chemical reactions have to take place to bind the oxygen to the hemoglobin and then unbind it at the point of tissue delivery.

So when the red blood cells are going through the lungs, you need oxygen from the lungs to bind to the hemoglobin and then when you get to the point of tissue delivery, you need the oxygen to unbind from the hemoglobin so it can go to the tissues.

Well in the course of all this reactions in the red blood cells. So as oxygen is bound and unbound from hemoglobin, in the course of that, some bad molecules are produced. Some molecules that could be dangerous to the red blood cell including hydrogen peroxide is one of those chemicals. You've probably heard of that.

And again, these bad molecules have the potential to damage the red blood cell and lead to the red blood cell's death. Now unfortunately, in G6PD deficiency, we're gonna have a little problem where red blood cells can become damaged. And the reason that this can happen is because that NADPH which required G6PD to get made, that facilitates another chemical reaction.

So we're now 6 different molecules in deep here and it's molecules 5 and 6 that ultimately convert the bad or dangerous chemicals like hydrogen peroxide to ones which are not dangerous and save the day for our friendly red blood cell.

00:39:02

So it's extremely complicated but the bottom line is this, there are reactions that take place as hemoglobin and oxygen bind and unbind that create chemicals that can be dangerous for red blood cells.

But there is another line of things happening which makes those dangerous chemicals not be so dangerous. And the very first phase of the reaction to create molecules that are gonna help and save the day is G6PD—this enzyme.

So if you don't have G6PD or most time what we're talking about is the G6PD as made but it's just not made correctly and we'll get more to that in a minute. Because it's not made correctly, you end up with not as much of the NADPH which you need.

So the red blood cell has to rely on other processes to turn dangerous molecules in to safe ones and as oxygen binds and unbinds from the hemoglobin. So hopefully, you're still tracking with me and if not, rewind a couple minutes and who knows, maybe I'll explain it the second time through. You can always hope.

So let's look at what causes then G6PD deficiency. Deficiency means you don't make enough of this enzyme, which I've described, ultimately, puts your red blood cells in jeopardy because you don't make enough of it. And I should say, you don't make enough of correctly formed G6PD.

And because of that, you don't get to molecules 5 and 6 that's gonna help your red blood cells, kind of, be saved from the dangerous things that are getting made. So let's think about why you don't have enough correctly functioning G6PD.

Well remember, the molecules and enzyme, it's a protein. Proteins are made in the cell using your genetic code. So, if you're born with genetic code that makes a faulty version of G6PD, that faulty version isn't gonna work as well in that crucial first step of this long complex chemical chain of reactions.

00:41:09

And so, in its basic level, G6PD is a genetic disorder. You don't have the right genetic code for the correct copy of this important enzyme. And because it has a genetic basis and genes are passed on from parents to children, we see cases of G6PD running in families and being more prevalent in particular ethnic groups where folks are marrying and having kids together. And we'll talk more about that in a moment.

First though, one more thing, just to add another layer of complexity this whole situation, the code for G6PD, that enzyme is located on the X chromosome, which is a sex chromosome. You remember boys have one copy of X cos they have X and Y and girls have two copies of X because they're X-X.

So all of their red blood cells have two X's and boys only have one X. So all boys with the faulty code are gonna make a faulty enzyme that doesn't work quite as well because they only have one copy of X and it's got the code on it that makes the faulty enzyme.

Girls, on the other hand, and this is particularly interesting, I think. In girls, even though they have two X chromosomes, only one X-chromosome in every cell is active. The other one is inactive and it's not always the same one.

So if a particular girl has one X-chromosome with the normal code to make this enzyme and the other X-chromosome has a faulty code then depending on which X-chromosome is active versus inactive, some of the red blood cells in that particular girl will have the normal enzyme and some red blood cells will have the abnormal enzyme.

So in other words, some of the red blood cells are gonna work fine and the other ones are gonna be more prone to damage depending on which X-chromosome is active in a particular red blood cell of that particular girl.

00:43:03

So that makes thing a little more complicated. And then, one final point to make as we consider genes and codes and proteins, there's this spectrum of what a faulty G6PD enzyme looks like. You know, some don't work well at all, some work a little bit, some mostly work.

So, you know, you can have a spectrum of severity with this disease based on exactly what that abnormal G6PD enzyme looks like when you know you're deficient in normal working G6PD. And for girls, there's gonna be a mix of red blood cells to consider.

Do they have mostly a faulty mix or mostly a normal mix depending on individual red blood cells? So the bottom line is the clinical expression of G6PD. In other words, the symptoms that we see really boil down to how close the normal, the faulty enzyme, behaves.

For some, the enzyme works pretty well and in others it doesn't work well at all. So there can be lots of variability. And then also in particular girls, how severe is it depending on—are most of your red blood cell's normal behaving or not normal behaving?

So let's talk about epidemiology—another big word, you know. Epidemiology is just looking at who gets this? You know, how common is it? Where is it? You know, where do you see it?

So let's begin with how common is G6PD deficiency. While I mentioned in the intro about how 400 million people worldwide are affected. And we do see some differences with regard, not only to ethnicity; we also see differences with regard to geographic location regardless of what your ethnicity is. But you lived in a certain area and your family has lived there for a certain long time.

So G6PD deficiency is seen most often in the tropical and sub-tropical zones of the Eastern Hemisphere. So Africa the Middle East, Southern Europe, parts of India and China. And here is another really interesting medical and historical tidbit for you.

00:45:03

The geographic region where we see G6PD deficiency the most closely matches the distribution of Malaria which is caused by a microorganism that's spread by mosquitoes and infects red blood cells. Well as it turns out, Malaria is not able to infect red blood cells quite as easily if you have G6PD deficiency.

It's not a hundred percent, you can still get Malaria, but it's less likely which may have selected this disorder in this geographic region. So you know, if you get Malaria and die, you're less likely to have children. And if G6PD deficiency protects you, somewhat, against Malaria, you're more likely to live, have children and pass on your genetic code.

And this also explains why Dr. Zucker in Israel sees more cases of G6PD deficiency than we see here in the United States although we do see it from time to time. And then as we consider ethnic groups, so not really talking about geographic locations now but ethnicity, about 60-70% of the Jewish Kurdish population is affected. So again, many of them now in Israel.

We also see this disorder in higher numbers in Nigeria where 22% of the population is affected. Here in the United States, African-Americans, around 12% of them are affected with G6PD deficiency.

About 6% of those living in Greece, another 6% of those living in South China and about 3% in India. Japan and Korea, about 1% of the population is affected. So that's sort of the different epidemiology where we see this—how common it is. Really sort of depends on who you're talking about and in what part of the world.

In terms of symptoms, it really depends. You know, it depends on how well your red blood cells can survive. So it depends on how well your faulty enzyme works. Again in women, what mix of red blood cells have the faulty versus the normal enzyme.

00:47:02

And then the help of other mechanisms within the red blood cell that can eliminate dangerous chemicals and how much of those dangerous chemicals are being produced. And there's some very distinct things that can lead to more dangerous chemicals being produced in the red blood cell and diminish stability of your body to take care of them.

And then these things are gonna trigger, you know, more of those dangerous chemicals and less of an ability to deal with them which then ultimately causes an increase in the destruction of red blood cells which ultimately leads to the symptoms that we see.

So what are those triggers? What are the things that can make it more likely that the bad chemicals get made and are not able to be dealt with and so then the red blood cell ends up dying?

Well one is just infection. Infection in the body whether it's a viral infection or a bacterial infection, you're more likely to have an issue when infections occur. Also certain medications especially sulfa antibiotics but there are others as well. Some foods like fava beans, as Dr. Zucker mentioned, and other chemical exposures including the chemical found in mothballs.

So, the list of chemicals and medications that can insight more red blood cell destruction in those with G6PD deficiency is fairly extensive. If you're interested, I'll include a link to them in the show notes for this Episode 396 over at pediacast.org.

It's a link from MedScape and it just has a long list of things that folks with G6PD deficiency should avoid because it makes it more likely that their red blood cells will become damaged.

So then, what symptoms do we see as red blood cells are destroyed? Well of course, the destruction of red blood cells leads to anemia which is what we call having a low number of red blood cells. You have less capacity to carry oxygen because you have fewer circulating and properly functioning red blood cells.

And so, you're not getting as much oxygen to your tissues and so we see fatigue, tiredness, exercise intolerance, headaches are also common, the skin may look paler than usual, and particularly there may be paleness to the lips, the tongue and inside the lower eyelid because the pink color of these tissues—so the lips, tongue and inside the eyelid, are in large part due to circulating red blood cells.

00:49:19

So if you have fewer of those, the pink turns pale. Now in the skin, this may be more difficult to appreciate because you have varying degrees of skin pigment depending on your ethnicity. And so, that can be more difficult to determine if paleness is present. But if you look at the lips, the tongue and the inside of the lower eyelids, that can really help you out because, again, that's gonna be pale for pretty much anyone depending, you know, it doesn't matter how much skin pigment that you have.

Okay, so we have anemia. It's also a hemolytic anemia. That's just a fancy way of saying the red blood cells are breaking apart and spilling their contents into the bloodstream which is a problem on many levels.

First, hemoglobin in the blood when it's not within red blood cells. It's fine if it's within the red blood cell. But if hemoglobin spills out, it becomes dangerous to the kidneys. So we can see kidney problems which can lead to kidney failure and severe cases.

The hemoglobin—you may start to see that urine has a darker color and then you start to see evidence that the kidneys aren't working as well. Second, we see jaundice or yellowing of the skin and eyes. And this is because the spilled hemoglobin is broken down into bilirubin as the body tries to get rid of it.

We can also see liver and spleen swelling which can lead to belly pain and back pain. So lots going on but the good news is in the absence of these triggers, most folks do well. And that's because that their baseline state of health, there is enough G6PD activity or some other protective functions to deal with the build-up of dangerous chemicals in the red blood cells to support life.

If these folks had no way to protect against the build up of these dangerous chemicals, they wouldn't have been born.

00:51:04

You know, because they would have had have an issue with the survival of red blood cells right from day one—from the time their first red blood cells were ever made. So at their base line, they have enough protection until some trigger comes along and makes things worse. So hope that makes sense.

In terms of diagnosis, there are other causes of hemolytic anemia—so the history helps a lot. You know, looking back you see patterns of illness, medication or chemical exposure that then leads to symptoms so that can give you a clue of what's going on.

G6PD deficiency can also present in the neonatal period, so soon after birth as severe or prolonged jaundice. And of course, you wanna consider family history given the genetic nature of the disease. Ultimately, there are several screening tests which are followed by more sophisticated blood testing to diagnose the condition.

And in some regions of the world, it's screened for at birth depending on how common it is in a particular area. In terms of treatment, you know, you wanna prevent hemolytic crisis. You wanna prevent the red blood cells from becoming damaged and rupturing, dying, releasing their contents into the bloodstream.

So you wanna avoid that long list of triggering chemicals including sulfa antibiotics, fava beans, mothballs along with lots of others. And again, I'll have that linked in the show notes if you wanna check that out.

You want infections taken care of and cared for as quickly as possible and then you wanna watch closely for any signs of hemolytic anemia which were those symptoms that we mentioned. If a crisis and hemolytic anemia do occur, you want expert medical attention right away. You may need IV fluids. You might need blood transfusions and care for possible kidney problems.

So there you go, G6PD deficiency. Now you know a little bit about a disease you might not have heard of before. But one, it does affect 400 million of your fellow human beings and special thanks to Dr. Zucker in Israel for suggesting the topic.

00:53:01

Don't forget, if you have a topic that you would like to suggest, it's an easy thing to do. Just head over to pediacast.org, click on the contact link and ask away.

[Music]

00:53:40

Alright, we are back with just enough time to say thanks to all of you for taking time out of your day and making PediaCast a part of it. Really do appreciate that. This was a science-filled show—I feel like. I feel like we went kinda deep into the science of laryngomalacia and G6PD deficiency.

So hopefully enjoyed that. Again, maybe listen—you know, if you're really interested in this and you're still like scratching your head a bit, maybe listen a second time through and it'll make a bit more sense to you.

Also wanna remind you, and I think this is really important. If you haven't seen the SpaceX Falcon Heavy Test Flight webcast, watch it with your kids. I mean, this is exciting stuff and I think, you know, if your kids like Star Wars, if they're really into space, I think they'd be very interested.

And it's not just the launch, you know. The launch is really cool, don't get me wrong, but the lead up to it and the explanation of what they're trying to do and where they wanna go with this is all very interesting. And so, check out that webcast. Again I'll have a link to it in the show notes for this Episode 396 over at pediacast.org.

Don't forget you can find PediaCast in all sorts of places. We're on iTunes, Google Play, iHeartRadio, Spotify—most mobile podcast apps. We also have a landing site, pediacast.org. You'll find our entire archive of past programs, also our show notes, transcripts, written transcripts, our terms of use agreement—very important, and our contact page if you wanna ask a question or suggest a topic for an upcoming episode.

00:55:08

Also, wanna remind you that PediaCast is part of the Parents On Demand Network, it's a collection of podcast for moms and dads, and that collection includes PediaCast along with many others.

There's a Parents On Demand Mobile app which you can find in the iOS app store, also in Google Play. And, you know, it's an easy way then to connect with all the shows that are part of the Parents On Demand Network.

Another one of the shows in that network that may be of interest to this audience is called Preggy Pals—the Preggy pals podcast. And I'll have a link to it in the show notes for you.

So if you're currently pregnant or you know someone who is, it's a terrific podcast. Past episodes include coping with morning sickness, keeping your pregnancy low risk, gestational diabetes, anxiety and depression during pregnancy, taking medications during pregnancy—really an entire treasure trove for those with a baby on the way.

So check that out, again, the Preggy Pal's podcast from the Parents On Demand Network and I'll put a link to it on the show notes for this Episode 396 over at pediacast.org.

Also, be sure to connect with us on social media. Pediacast is on Facebook, Twitter, Google Plus, Pinterest. And of course, we really appreciate it when you share the show with your own online audience but not only online, also that face-to-face interaction.

Let your family, friends, neighbors, co-workers, babysitters, grandparents, anyone who takes care of kids or has kids of their own then let them know about this podcast—evidence-based information.

Hopefully, in terms parents can understand. I know I got a little confusing today, there were some big words. Hopefully, we broke it down enough for you.

Also let your child's teacher know, their pediatric medical provider so they can share the show with their other patients and families. And then, let your doctor know that we have a program for them too. It's similar to this program called PediaCast CME.

00:57:03

CME stands for Continuing Medical Education. We turn the science up a couple notches, not as many explanations of those big words. And we offer free Category I-Continuing Medical Education credit for those who listen. Shows and details are available at the landing site for that program which is pediacastcme.org.

That show is also on iTunes, Google Play, iHeartRadio, Spotify—most mobile podcast apps. Simply search for Pediacast CME.

Alright, speaking of watching things with your kids, you know, we don't want too much screen time. You know that's very important to have face-to-face interaction and doing stuff, being active with your kids.

But I will say this, the Olympics are starting. And so, you'll probably hear me talking about that here in some future episodes cos I always love watching the Olympics. So do that with your kids but don't just stare at the screen, you know, talk about it, interact, engage, you know, say, "Hey, what do you think that person's training schedule looks like?"

And you know, just make it a point of conversation but also a fun thing to do together.

Alright, thanks again for stopping by and until next time, this is Dr. Mike saying stay safe, stay healthy, and stay involved with your kids. So long, everybody!

[Music]

00:58:29

Announcer 3:This program is a production of Nationwide Children's. Thanks for listening! We'll see you next time on Pediacast.